1. Field of the Invention
The present invention relates to a cabinet for housing electrical components.
2 Description of the Related Art
FIGS. 9 through 10 show an embodiment of an all-weather type cabinet, which is similar to that disclosed in detail in U.S. Pat. No. 4,949,218 in the name of the present applicant, enclosing therein electrical components, such as communication equipment, in such a way that two apparently opposite requirements are met, respectively, for an enclosed construction wherein the communication equipment is not subject to direct exposure to rain and other weather, and an open construction wherein there is provided a passage for releasing heat to the exterior.
FIG. 9 is a perspective view showing the entire cabinet, FIG. 10 is a front sectional view of a pertinent part of the cabinet taken in a plane along line 10--10 in FIG. 9, and FIG. 11 is a lateral side sectional view of the pertinent part of the cabinet taken in a plane along line 11--11 in FIG. 9.
As shown in these figures, a horizontal passage is formed for ventilation, extending crosswise (widthwise of the cabinet) and horizontally through a ceiling portion 41a of the cabinet 41, and which encloses therein communication equipment 45. At each end of the horizontal passage 42 there is installed a cooling fan 43 (ventilation means) which forcibly draws in outside air through a vent 43a at one end of the horizontal passage 42, delivers the air therethrough, and exhausts said delivered air to the exterior through a vent 43b at the other end thereof.
The horizontal passage 42 of the ceiling portion 41a and the cabinet interior housing portion 44, the latter holding communication equipment 45, are partitioned from each other by partition 41', whereby moisture, dust and dirt, etc., contained in air flowing through the horizontal passage 42 are prevented from entering the cabinet interior housing portion 44. At respective key points of the cabinet interior housing portion 44 there are furnished posts 46, each of which is vertically arranged as a base, or support, on which a respective part of the communication equipment 45 is supported.
The partition 41', which separates the horizontal passage 42 of the ceiling portion 41a and the cabinet interior housing portion 44, includes a part 47 which extends along the direction of the air flow inside the horizontal passage 42 and has a plurality of fins 48 (of a thermal conductive material) extending therethrough. These cooling fins 48 have a configuration of a large number of vertically oriented flat fins extending horizontally, crosswise of the cabinet and through the part 47 of the partition, and thus parallel to the horizontal passage 42; further, the fins are joined at the centers thereof. The upper parts of these fins, defined in reference to the centers thereof at which the fins are joined together, extend upwardly within the horizontal passage 42 of the ceiling portion 41a, and the lower parts thereof extend downwardly within the cabinet interior housing portion 44.
The cooling fins 48 are configured such that air, moving upward as it is heated by heat radiated by the communication equipment during operation, is cooled (heat absorption) by the lower parts of the cooling fins 48 and descends toward the lower parts thereof, with the removed heat subsequently being radiated (i.e., the heat is exhausted) by the fin upper parts into the cool air flowing inside the horizontal passage 42 and exhausted by the air flow to the exterior. This continual heat transfer from the cabinet interior to the horizontal passage 42, due to the heat absorption and heat radiation by the cooling fins 48, effectively cools the cabinet interior 44.
From the viewpoint of accident prevention and safety, it is dangerous to lay, at a lower part of the cabinet interior, a variety of cables 51 used for electrical connections between equipment 45 within the cabinet housing portion 44 and exterior devices, and thus L-shaped channels 52 are formed from sheet metal and mounted at the upper part of each post 46, to carry the cables 51 and thereby safely house them within the cabinet, as shown in FIG. 11.
Nevertheless, when the above-disclosed cooling mechanism, which effectively cools the cabinet interior housing portion 44 with the cooling fins 48, is used, heated air accumulates in an upper space in the cabinet, as in the prior art, and thus cables 51 laid in the upper part of the cabinet interior housing portion 44, without thermal protection, inevitably are thermally affected. In addition since there may be some power cables, etc. among these cables, each carrying a large current and generating heat, it is likely that the cable jackets would be damaged during long term use.